One main theory behind the origin of
tinnitus is based on the idea that alterations of the spontaneous electrical activity within the auditory system lead to abnormal firing patterns in the affected nervous structures [1]. A possible therapeutic option is the use of electrical stimulation of the auditory nerve for the recovery or at least limitation of the abnormal firing pattern to a level that can be easily tolerated by the patient. The Tinnelec Implant consists of a single non-penetrating stimulation
electrode connected to a Neurelec
cochlear implant system. As a first feasibility study, before starting implantations in hearing patients, we thought to assess the potential of the Tinnelec stimulation to treat
tinnitus in unilateral deaf patients, analysing hereby its effectivity and risks. Three patients suffering from unilateral
tinnitus resistant to pharmacological treatment and ipsilateral severe to profound
sensorineural hearing loss/
deafness were implanted with a Tinnelec system between September 2007 and July 2008, at the ENT Department of Hannover Medical School. The stimulation strategy was chosen to induce alleviation of the
tinnitus through suppression, masking and/or habituation and the response of each patient on the treatment was monitored using a visual analogue scale (VAS) on loudness and annoyance of
tinnitus, mood of the patient, as well as the
tinnitus handicap inventory (THI). All patients had a benefit from the electrical stimulation for their
tinnitus (THI-score improvement of 20-70), however, not all participants profited from the Tinnelec system in same way and degree. In one patient, despite good results, the device had to be replaced with a conventional
cochlear implant because of Tinnelec-independent increase in
hearing loss on the contralateral ear. Additionally, due to the extension of
cochlear implant indications, the devices of the other two patients have been meanwhile replaced with a conventional
cochlear implant to benefit additionally from hearing improvement. As demonstrated in the present study, sensorineural
tinnitus in humans may be suppressed/masked/habituated by electrical stimulation. The main advantage of the Tinnelec implant would be the option to treat patients with normal and usable hearing, stimulating the affected ear with the cochlear non-penetrating stimulation
electrode of the device, and extend the treatment in cases of progressive
hearing loss by explanation and
reimplantation with a penetrating
electrode addressing
tinnitus as well as the
hearing impairment. The present study is the first report on a long-term follow-up on
tinnitus patients implanted with Tinnelec. Further clinical studies to implant
tinnitus patients with residual or normal hearing on the affected ear are on the way.